"I kept my hair. I lost my manhood," one former Propecia user who is suing Merck told Marshall. (Getty Images/blazic27)

(Newser)
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It's a little pink pill taken once daily and prescribed to millions of men. A sliver of those users allege it was a devastating choice. Writing for Tonic, Lisa Marshall reports a class-action suit against Merck over finasteride, better known as Propecia, will be heard late next year. In the meantime, Marshall looks at the history and science behind the drug, taken by men with prostate issues or to combat hair-loss. Some young men who took it for the latter condition claim that after abandoning the drug, the extreme side effects—depression that some families allege have driven the men they love to suicide, a total loss of sex drive, or the inability to have an erection—didn't go away. That they're taking it in the first place is thanks to a group of "male pseudo hermaphrodites" in the Dominican Republic, Marshall explains.

In the early 1970s, endocrinologist Julianne Imperato-McGinley decided to investigate the stories out of Salinas, where a couple dozen children born as girls turned out not to be: Their testicles and penises were unnoticeable at birth, but the rush of testosterone that came at puberty enlarged their genitals, revealing the truth. Her 1974 paper on her find pointed to the subjects' lack of enzyme 5-alpha reductase. Without it, testosterone isn't converted into the "far more potent" hormone dihydrotestosterone (DHT). The head of research for Merck zeroed in on Imperato-McGinley's observation that the subjects didn't experience a receding hairline: DHT has a negative effect on hair follicles, and they didn't have much of it. And so Merck created finasteride, which inhibits 5-alpha reductase, and in 1997, got approval to market it as a hair-loss treatment. Some now allege taking it was a colossal mistake; Marshall looks at why.